Claire is the head of the Leonelli crime family and also holds the title of vampire, which is Judoh's version of the Godfather. Because of his upbringing he is mentally unstable and likes to play games and torment his enemies.
Claire is the son of Lorenzo Leonelli who was the former vampire (mafia don) and respected head of the Leonelli crime family. With the death of his father in the first episode Claire assumes the role of vampire even though he is still only 19. During the funeral Claire sets off a hand grenade which gets tossed out of the cemetery and we can clearly see that Claire is quite literally nuts. This is due to the fact that he did not have an emotionally stable childhood which was caused by many factors the primary one being that his father never once showed him any affection and the only attention he got from his father was when his father was trying to teach him to be his successor. In one flashback we see Claire as a young boy sitting down to dinner only to be attacked from under the table. His father told him it was to teach him to always be aware of enemies. When Claire’s mother died, rather than help him through it himself, Claire’s father took a boy from the slums and brought him to the Leonelli home to be a friend for Claire. This was Giovanni who is now one of the Leonelli enforcers. His father also made him feel worthless and constantly taunted him saying he was not good enough to be the heir the Leonelli family business. Due to all of this Claire despised his father and showed signs of pure joy at the funeral.
Claire could easily be compared to The Joker, from the DC comics, as he likes to throw hand-grenades and refers to them as fireworks, and he has a maniacal laugh similar to the Joker. He also likes to play games with his enemies and torment them until he gets bored. In one instance there is a poet who owes the family money and Claire makes him write poem after poem and each time tells the poet that he hates them and if he does not write a good one he is going to die; Claire had no intention of killing the poet but wanted to make him believe he would die, just for Claire’s enjoyment. While he is crazy Claire is very intelligent and believes himself to be better than everyone else. Being a mafia boss Claire has to deal with a lot of low-life’s and bandits and the majority of the people he deals with disgust him and he sees them as trash. What really annoys him is when this low life scum think they are better than Claire, and in one instance Claire becomes enraged when a common hitman thinks of himself as an artist. The only people that ever really seemed to interest him were Boma and Daisuke. In the case of Daisuke we can again draw a comparison to the Joker as though technically they are enemies Claire has no desire to kill Daisuke as things are much more fun and less boring with Daisuke around. Claire is also pretty fearless and in one episode takes part in a game of Russian roulette at his own casino just for fun and in another episode when a rival mafia boss does not show him respect he shoves a hand-grenade in his mouth.
He is voiced by Daisuke Sakaguchi (Japanese), and Johnny Yong Bosch (English). Johnny Yong Bosch is a name that anime fans should recognise as he also provides the voice of Vash the stampede in Trigun and Ichigo Kurosaki in Bleach and also Kaneda in Akira. He may also be recognised as having appeared in several seasons of the Power Rangers TV show.